1. The Field of the Invention
This invention relates to pressurized fluid transfer and, more particularly, to novel systems and methods of a closed circuit fuel nozzle.
2. The Background Art
It is often necessary to pump a fluid from one location to another. A nozzle may provide an interface that enables the fluid transport system (e.g. hose) to engage a tank to which a fluid (e.g. fuel) is being pumped. When it is necessary or desirable to pump at faster speeds and volumetric flow rates, it may be advantageous to provide a sealed or closed circuit system. In such situations, the nozzle may seal with an interface to provide a closed, sealed path for the fluid to travel from source to destination. The closed circuit design allows for higher fluid pressures for increased volumetric flow while preventing leakage.
Current closed circuit nozzles have several shortcomings. Typical nozzles are susceptible to wear. Wear becomes particularly apparent on the exterior sides of the fuel tank adapter. Several current nozzle designs seal against the exterior sides of the adapter. As a result, after limited use seal performance degrades and leaks begin. To avoid this problem, some nozzles seal against the end face of the adapter. Typically, the end face is not exposed to abrasion like the exterior sides. While an improvement, these abutment sealing nozzles are still very susceptible to wear. For example, with use, a nozzle may begin to sag when secured to the adapter. The sag may cause a missalignment between the abutment seal and the end face of the adapter resulting in leaks.
Current nozzles are also susceptible to contamination by dirt and grit. Dirt and grit can enter a nozzle and increase friction resistance to nozzle cycling. The increased resistance may prevent a nozzle from completely closing once the closing process has begun. Large, unprotected sliding surfaces, found in may current nozzles, are particularly prone to dirt and grit contamination.
In the event that a careless operator drives a vehicle away with a nozzle still attached, current nozzles do not provide a safety to prevent catastrophic nozzle failure and associated large scale fuel spills. Moreover, current nozzle designs are heavy and awkwardly shaped. A cumbersome nozzle often costs the operator extra strain and expenditure of effort as well as bruised knuckles and the like.
What is needed is a closed circuit fuel nozzle that provides seal articulation and motion to accommodate misalignment caused by wear. The nozzle should also minimize the size of sliding surfaces to lower nozzle cycling friction, thus insuring predictability and complete closure. The nozzle may provide a safety system to prevent fuel spills in the event of a nozzle break. Such a nozzle may be packed in a lightweight, ergonomic body formed to complement the hands of an operator.
A closed circuit fuel nozzle in accordance with the present invention may be formed to engage a fuel tank adapter. In certain embodiments, the nozzle may have a body comprising an inlet aperture, a tubular assembly extending in a longitudinal direction, and walls forming a closed flow path from the inlet aperture to the tubular assembly.
In certain embodiments, a receiver may secure to the body to receive the fuel tank adapter. In an alternative embodiment, the receiver may be formed as part of the body. The receiver may house the tubular assembly and provide alignment between the tubular assembly and the fuel tank adapter. A distal end of the tubular assembly may form an outlet aperture from which fuel exits before entering the adapter.
The tubular assembly may translated in the longitudinal direction within the receiver. In certain embodiments, the tubular assembly consists of a tube extending in the longitudinal direction and a sealing collar secured proximate the distal end of the tube to form the outlet aperture. An articulator may be positioned between the tube and the sealing collar to provide resilient articulation of the sealing collar. The resilient articulation may permit the sealing collar to match the angle of the end face on the fuel tank adapter, thus ensuring a proper seal. In certain embodiments, a clamp may mechanically limit translation of the sealing collar with respect to the tube in the longitudinal direction.
A bias member may be positioned between the tubular assembly and the receiver to urge the tubular assembly in the longitudinal direction. The biasing member may provide resilient translation of more than 0.5 inches of the tubular assembly with respect to the body. In selected embodiments, the biasing member may be a coil spring aligned with the longitudinal direction to encircle the exterior of the tube. Thus, the spring may be positioned external to the flow path. A poppet valve selectively translatable in the longitudinal direction may be shaped to stop flow through the body when seated against the sealing collar in the longitudinal direction.
An actuator may be connected to the poppet valve to provide motion in the longitudinal direction thereto in response to a pressure communicated from the flow path. In certain embodiments, the poppet valve has a stem extending in the longitudinal direction to engage the actuator. The stem may have a pipette conduit formed substantially longitudinally therethrough to communicate the pressure within the flow path to the actuator. The actuator may include a piston translating in the longitudinal direction in response to the pressure communicated from the flow path via the pipette conduit to a selected side of the piston.
A closed circuit fuel nozzle in accordance with the present invention may be configured to fracture in a controlled manner so as to avoid fuel spills. In certain embodiments, the receiver of the nozzle may be scored to produce a weakened fracture line. Thus, in the event that a careless operator drives away with a nozzle still attached to a vehicle""s fuel tank, the receiver is weakened to fracture at a specific location. The specific location may be selected such that the ability of the nozzle to stop flow therethrough is unaffected by a fracture.